1. Field of the Invention
The present invention relates to a golf club head.
2. Description of the Related Art
In general, a plurality of parallel linear grooves are formed in the face surface of a golf club head to extend in the toe-to-heel direction (for example, Japanese Patent Laid-Open Nos. 2002-224250 and 2004-141277). These grooves are called, for example, scorelines, marking lines, or face lines (they will be referred to as scorelines in this specification). These scorelines have an effect of increasing the back spin amount on a struck golf ball, or suppressing a significant decrease in back spin amount on a struck golf ball upon a shot in rainy weather or that from the rough. A technique of forming grooves finer than scorelines in the face surface to increase the back spin amount, and suppress a decrease in back spin amount in, for example, rainy weather has also been proposed (for example, Japanese Patent Laid-Open Nos. 2011-234748 and 2011-234749).
The use of only scorelines has a limit in the effect of increasing the back spin amount, and suppressing a decrease in back spin amount in, for example, rainy weather. Especially in an athletic golf club head, the specifications of scorelines are subject to a constraint associated with a specific rule, so it is difficult to further increase the back spin amount. It is therefore desired to further improve the effect of increasing the back spin amount, and suppressing a decrease in back spin amount in, for example, rainy weather, using grooves finer than scorelines.